Cartridge strip advancing mechanism for fastener driving tool

Abstract

In a powder driven fastening tool, a channel is included for feeding a strip of explosive powder cartridges to a firing mechanism. A trigger is included for actuating the firing mechanism, wherein the trigger is movable between a first position and a second position. An advancing lever is pivotally coupled to the tool, the advancing lever having a strip engagement portion for indexing the strip which extends into the channel. An advance link is cammingly engaged with the advancing lever and is operationally associated with the trigger so that the strip engagement portion is in a first position in the channel when the trigger is in the first position and so the strip engagement portion is in a second position when the trigger is in the second position.

What is claimed is:  
     
         1 . A powder driven fastening tool comprising: 
 a channel for feeding a strip of cartridges to a firing mechanism;    a trigger for actuating the firing mechanism, the trigger being movable between a first position and a second position;    an advancing lever pivotally coupled to the tool, the advancing lever having a strip engagement portion extending into the channel for indexing the strip;    an advance link cammingly engaged with the advancing lever and operationally associated with the trigger;    the strip engagement portion being in a first position in the channel when the trigger is in the first position; and    the strip engagement portion being in a second position in the channel when the trigger is in the second position.    
     
     
         2 . A powder driven fastening tool according to  claim 1 , wherein the advance link further comprises a cam pin and the advancing lever further comprises a ramped cam slot, whereby the advancing lever pivots as the cam pin of the advance link follows the ramped cam slot of the advancing lever.  
     
     
         3 . A powder driven fastening tool according to  claim 2 , wherein the cam pin is located at a first position along the cam slot when the trigger is in the first position, and wherein the cam pin is located at a second position along the cam slot when the trigger is in the second position.  
     
     
         4 . A powder driven fastening tool according to  claim 1 , wherein the advancing lever is pivotally coupled to the tool by a pivot pin, whereby the strip engagement portion is disposed on one side of the pivot pin and the advancing lever is cammingly engaged with the advance link on another side of the pivot pin.  
     
     
         5 . A powder driven fastening tool according to  claim 4 , wherein the pivot pin is connected to a housing of the firing mechanism.  
     
     
         6 . A powder driven fastening tool according to  claim 1 , further comprising a firing chamber positioned along the channel between a barrel of the tool and the firing mechanism, the strip engagement portion being positioned toward the firing chamber when the strip engagement portion is in the first position, the strip engagement portion being positioned away from the firing chamber when the sleeve is in the second position.  
     
     
         7 . A powder driven fastening tool according to  claim 1 , further comprising a spring disposed between the trigger and a housing of the tool, wherein the spring biases the trigger to the first position, whereby the trigger is movable to the second position against the bias of the spring.  
     
     
         8 . A powder driven fastening tool according to  claim 1 , wherein the strip engagement portion includes a pawl for engaging with a notch of the cartridge strip.  
     
     
         9 . A powder driven fastening tool according to  claim 8 , wherein the pawl is engaged with a first notch of the cartridge strip when the strip engagement portion is in the first position, and wherein the pawl is engaged with a second notch of the cartridge strip when the strip engagement portion is in the second position.  
     
     
         10 . A powder driven fastening tool according to  claim 8 , wherein the advancing lever further comprises a spring for biasing the pawl into engagement with the notch, wherein the pawl is movable into disengagement out of the notch against the bias of the spring.